I'd like to think that the Galaxies performed well in the Dominion War, as we saw them in battle plenty of times but never destroyed like every other class out there (even the Defiant!), so it could be that they're tough and still pack quite a wallop. But since the Dominion War isn't really TNG-related, and they were, like many others, merely pawns.
This is pure conjecture, but I imagine that the Galaxy could draw fire while simultaneously providing support fire in fleet battles; tough enough to tank, but hanging back so that other ships focus on offense, and being the command ship of an armada or task force. It's the impression I got during the final battle of the war, but again, that's guesswork and wishful thinking on my part.
But then that all sidesteps the Sovereign's design. I'm not against the idea of a tougher ship with more teeth, I just wish the Sovereign didn't look like that
Ah well, it's an 18-year old design already.